The present invention relates to a transportation system of a floated-carrier type, and more particularly, to a transportation system of a floated-carrier type which comprises a guide rail, composed of main and branch lines, in order that a carrier can be transferred from the main lines to the branch lines.
To increase office or factory automation, transportation systems have recently been installed in some buildings. Such systems are used to transport slips, documents, cash, samples, or the like, between a plurality of locations in the buildings.
In order to avoid spoiling the environment of the offices or factories, transportation systems of this type are expected not to produce dust or high levels of noise. Thus, in one such conventional transportation system, described in U.S. patent application No. 726,975, filed previously by the inventor hereof, a carrier is kept floating, in a non-contact manner, above a guide rail, by means of an electromagnetic attractive force acting between the carrier and the rail, when the carrier is propelled along the rail.
The carrier must be transported smoothly to various locations in a building, and, to attain this, the guide rail is composed of main lines, connecting principal locations in the building, and branch lines, which diverge from the main lines and connect various secondary locations therein.
It is necessary, therefore, to provide means for transferring the carrier, running along the main lines, to the branch lines, and vice versa. Prior art examples of a transfer means or apparatus are disclosed in the following publications:
U.S. Pat. No. 4,109,584 describes a transportation system, which is provided with a rail-switching device at a diverging section, where branch lines diverge from main lines. When the switching device is operated mechanically, the main lines are disconnected from one another, and are connected to the branch lines, so that a carrier can be transferred from the main lines to the branch lines.
In a system described in Japanese Patent Disclosure No. 50-150112, no rail-switching device is provided, and main and branch lines are connected directly at a diverging section. A guide plate is provided at the diverging section, whereby the rollers of a carrier are guided from the diverging section to the branch lines. As the rollers slide along the guide plate, the carrier is transferred from the main lines to the branch lines.
As has been described above, however, the apparatus for transferring the carrier, from the main lines to the branch lines, requires a mechanical switching device. Therefore, the transfer apparatus is increased in size, thereby reducing the available space in the office. Moreover, the switching device is operated mechanically, and, especially in the system described in Japanese Patent Disclosure No. 50-150112, the rollers of the carrier are in contact with the guide plate while the carrier is being transferred. As a result, noise is produced by the transfer apparatus.
Thus, such a transfer apparatus is liable to spoil the environment of the office, in which case the main lines should not be provided with transfer apparatuses. In this therefore, the carrier cannot run smoothly along the guide rail, and can reach its destination only after a long period of time.